Devices for variable traffic flow templates

ABSTRACT

The invention discloses a user terminal ( 115 ) for a wireless communications system ( 100 ) which is arranged to establish and carry out a communications session with a gateway node ( 120 ) in the system ( 100 ) according to a first protocol over at least one bearer ( 110, 140 ). The user terminal ( 115 ) is arranged to provide a predefined issued message to the gateway node ( 120 ) during the establishment of a session with an indicator that the user terminal ( 115 ) is arranged to handle traffic to and from the gateway node ( 120 ) using a predefined version of a defined filter ( 130 ).

CROSS REFERENCE TO RELATED APPLICATION(S)

This application is a 35 U.S.C. §371 National Phase Entry Applicationfrom PCT/EP2009/008140 filed Nov. 16, 2009, designating the UnitedStates, the disclosure of which is incorporated by reference herein inits entirety.

TECHNICAL FIELD

The present invention discloses a user terminal and a gateway node in awireless communications system for variable traffic flow templates,TFTs.

BACKGROUND

In wireless communications systems such as, for example, the 2G/3G GPRSsystem, i.e. the General Packet Radio System, and the Evolved PacketSystem, EPS, the systems are arranged for communication between agateway node and one or more user terminals. In GPRS systems, thegateway node is known as the GGSN, the Gateway GPRS Support Node, and inEPS systems, the gateway node is known as the PDN-GW, the Packet DataNetwork Gateway.

The communication between the gateway node and the user terminal takesplace over a so called a Packet Data Network connection, a PDNconnection, over one or more so called bearer, an IP-CAN bearer,IP-Connectivity Access Network bearer, and the gateway node uses afunction known as the BBF, the Bearer Binding Function, to identifywhich bearer that a specific downlink packet should be transmitted via.The BBF in turn uses a filter known as the TFT, Traffic Flow Template,in order to “bind” packets” to the proper bearer.

The term “bearer” here refers to a logical IP transmission path betweena user terminal and the network with a specific Quality of Service, QoSproperties such as, for example, capacity, delay, packet loss error rateetc.

For GPRS systems, the IP-CAN bearer is a PDP-context (Packet DataProtocol), and for EPS systems it is an EPS bearer.

The TFT is used by the so called Bearer Binding Function, BBF, in agateway node in the system to bind downlink IP-packets to the existingbearers of a PDN connection, and might also be used to perform uplinkbearer verification, i.e. to make sure that a user terminal doesn't senddata packets using the wrong bearer.

In GPRS applications, the BBF is located in the GGSN, the Gateway GPRSSupport Node, and in EPS applications, the BBF is located in a gatewayGW node, a GW node, such as, for example, the PDN-GW, Packet DataNetwork GW, or the Serving GW for 3GPP accesses, or in the Access GW fornon-3GPP based access.

It can be noted that the term Bearer Binding Function is normally onlyused in 3GPP specifications related to PCC, Policy and Charging Control.However, the term is used here in order to reference the entity orfunction that encompasses the functionality involved in setting up andmanaging bearers in the applicable architecture i.e. the GGSN for GPRS,the PDN-GW for GTP-based EPC, the Serving GW for 3GPP access via aPMIP-based EPC or the Access GW for non-3GPP access via PMIP-based EPC.

SUMMARY

It is an object of the present invention to provide improvedfunctionality in the connection between a user terminal and a gatewaynode in a system such as those described above. The improvedfunctionality should allow for the use of multiple various versions of asignaling protocol, and should also be backwards compatible, i.e. itshould not exclude equipment which cannot handle newer versions of acertain protocol.

Such improved functionality is offered by the present invention in thatit discloses a user terminal for a wireless communications system whichis arranged to establish and carry out a communications session with agateway node in the system according to a first protocol over at leastone bearer.

The user terminal of the invention is arranged to provide a predefinedmessage to the gateway node during the establishment of a session withan indicator that the user terminal is arranged to handle traffic to andfrom the gateway node using a predefined version of a defined filter.

In one embodiment, the user terminal of the invention is arranged toalso receive a response from the gateway node to the predefined message,and the user terminal is also arranged to identify an indicator in thisresponse, the indicator indicating that the gateway node can transmitand receive messages according to said defined filter. In thisembodiment, the user terminal is arranged to format messages it sends tothe gateway node according to a predefined other version of the filterif the indicator is missing.

In one embodiment of the user terminal of the invention, the firstprotocol is the IP-protocol, the Internet Protocol, the predefinedmessage is the PCO, the Protocol Configuration Options, and the definedfilter is the TFT, Traffic Flow Template.

In one embodiment, the user terminal of the invention is a UE, a UserEquipment, of an EPS system, an Evolved Packet system.

In one embodiment, the user terminal of the invention is an MS, a MobileStation, of a GPRS system, a General Packet Radio Service system.

In addition to the user terminal described above, the invention alsodiscloses a gateway node for a wireless communications system, which isarranged to establish and carry out a communications session accordingto a first protocol with a user terminal in the system over at least onebearer.

The gateway node of the invention is equipped with a function forchoosing the proper bearer for messages to the user terminal, and isarranged to receive an indicator in a predefined message from the userterminal during the establishment of a session. If this indicator isreceived, the gateway node of the invention is arranged to use apredefined version of a defined filter when choosing the proper bearer.

In one embodiment of the gateway node of the invention, the firstprotocol is the IP-protocol, the Internet Protocol, the predefinedmessage is the PCO, the Protocol Configuration Options and the definedfilter is the TFT, Traffic Flow Template.

In one embodiment of the gateway node of the invention, the function forchoosing the proper bearer is the Bearer Binding Function.

In one embodiment, the gateway node of the invention is a PDN-GW, aPacket Data Network Gateway, for an EPS system, an Evolved PacketSystem.

In one embodiment, the gateway node of the invention is a GGSN, aGateway GPRS Support Node, for a GPRS system, a General Packet RadioSystem.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in more detail in the following, withreference to the appended drawings, in which

FIG. 1 shows a schematic overview of some of the components in a systemin which the invention is applied, and

FIG. 2 shows a sequence diagram when the invention is used, and

FIG. 3 shows a basic flow diagram in a UE/MS of the invention, and

FIG. 4 shows a basic flow diagram in a BBF in a gateway of theinvention.

DETAILED DESCRIPTION

FIG. 1 shows an example of a system 100 in which the invention isapplicable: in the system 100, there is a user terminal 115, shown bothas a UE/MS, since the invention can be applied both in GPRS systems,General Packet Radio Service system, in which the user terminals arereferred to as a UE, User Equipment, and in EPS systems, Evolved PacketSystem, in which the user terminals are referred to as an MS, a MobileStation.

The UE/MS communicates with a node 120 known as the GGSN in the GPRScase or the PDN-GW in the EPS case. These abbreviations stand for thefollowing:

GGSN: Gateway GPRS Support Node,

PDN-GW, Packet Data Network GW.

The communication between the UE/MS 115 and the GGSN/PDN-GW 120 takesplace over so called bearers, two of which are shown, a default bearer110 and a dedicated bearer 140. As the name implies, the dedicatedbearer 140 is dedicated to a certain kind of traffic or service betweenthe UE/MS and the GGSN/PDN-GW, examples of such traffic or servicesbeing voice or streaming of data. The default bearer 110 is used fortraffic for which there is no suitable dedicated bearer.

In order to direct traffic and or data to the UE/MS 115 via the correctbearer, the GGSN/PDN-GW utilizes a function 122 known as BBF, the BearerBinding Function, which in turn utilizes so called Traffic FlowTemplates, TFTs, shown as 130 in FIG. 1. The TFT comprises a number ofparameters in order to direct the traffic to the correct bearer, onesuch parameter being the IP address of the “target” UE/MS.

The communication between a so called remote endpoint node and the UE/MS115, via the gateway node 120, takes place according to the IP-protocol,i.e. the Internet Protocol. There are different versions of theIP-protocol, one of which is version 6, i.e. IPv6, in which, as opposedto the previous version, i.e. IPv4, the address for the UE/MS comprisesa prefix and an interface identifier. The full IPv6 address (prefix andinterface identifier) is part of a new TFT format, in order to directtraffic to the proper bearer, due to the fact that multiple interfaceidentifiers may be used by the UE/MS itself or devices on a networkbeyond the UE/MS. As opposed to this, IPv4 in present accesses onlycomprises one complete address, which is not part of the TFT filter, forthe UE/MS. Thus, detailing the UE/MS address is only applicable if thegateway node is arranged to operate according to IPv6; if the gatewaynode is arranged to operate according to IPv4, there is no need fordetailing the UE/MS address in the TFT filter further from what isalready know for the UE/MS.

According to the invention, the UE/MS 115 can find out if the gateway120 can use TFTs according to IPv6 or IPv4 in the following manner:

Introduce a new indicator into the Protocol Configuration Options, PCO,field that is sent from the MS/UE to the BBF when establishing asession, i.e. at the Primary PDP-context activation for 2G/3G GPRSsystems, and in the Initial attach or UE Requested PDN connectivityprocedure for EPS systems, the indicator signaling to the gateway thatthe MS/UE understands the new extended TFT definition according to IPv6and is capable of originating TFT filters using the extended definition.If the gateway node, i.e. the BBF does not understand the indicator, theBBF will simply ignore the indicator, which is standard procedure withunknown messages or indicators.

Introduce in the response from the BBF to the MS/UE in the Primary PDPcontext activation procedure and in the Initial attach procedure a newindicator in the PCO field that informs an MS/UE that the network, i.e.the gateway node or in this case its BBF, supports the new TFT-format,i.e. that of IPv6. The network will use the new TFT format only if boththe MS/UE indicated support for TFT extensions in the request and if thecore network, i.e. in this case the BBF in the gateway node, supportsthe new TFT format.

In this manner, the introduction of the following additions to theexisting TFT will be enabled in a manner that is fully backwardscompatible:

-   -   Addition of the full local IPv6 address, possibly masked, to the        list of TFT filter attributes;    -   Addition of the address type to the list of TFT filter        attributes.

Thus, according to the invention, support in the UE/MS for TFTenhancements using the possibilities of IPv6 is indicated in theProtocol Configuration Options from the MS/UE to the BBF.

The inclusion of the indicator according to the invention from the UE/MSis used by the BBF to determine if the extended TFT format should beapplied, or if the “legacy” TFT format should apply for the applicablePDN connection of a given UE/MS.

The inclusion of the indicator of the invention from the gateway node isused by the MS/UE 115 to determine if the extended TFT format shouldapply, or if the “legacy” TFT format should apply for the PDNconnection.

The logic of the invention to indicate the use of TFT enhancements ornot is applied when the indicator in the PCO field is provided for theprocedures when the first PDN connection to an APN, Access Point Name,is established for a UE/MS. Procedures for which this is applicable areshown in table 1 below:

TABLE 1 Procedure Reference PDP Context Activation Procedure for A/Gb TS23.060 PDP Context Activation Procedure for Iu mode TS 23.060 PDPContext Activation Procedure steps (A) using S4 TS 23.060 E-UTRANinitial attach TS 23.401 UE Requested PDN connectivity TS 23.401 InitialE-UTRAN attach with PMIP-based S5 or S8 TS 23.402 UE Requested PDNconnectivity with PMIP-based S5 or S8 TS 23.402

For the case when a PMIPv6 (Proxy Mobile IP) based EPC (Evolved PacketCore) is deployed in the network, and the BBF is located in the AccessGW/Serving GW (depending on whether the access is 3GPP or non-3GPPbased), there is the possibility that the BBF may be relocated duringthe lifetime of the PDN connection, e.g. during Access GW/Serving GWrelocation. For this particular case, it is considered a networkconfiguration issue to ensure that the use of the extended TFT format isonly indicated by the network at PDN connection establishment in thecase that the extended format is supported by all BBFs in the networkthat the PDN connection may be relocated to.

FIGS. 2-4 show sequences and flow charts of the general case, i.e. thestationary case, when the BBF is not relocated. In those figs, the GWnode can either be a GGSN or a PDN-GW, a Serving GW or an Access GW,depending on the scenario.

Turning now to FIG. 2, there is shown a general sequence diagram of theinvention that is applicable for all of the procedures listed intable 1. Only the Non-Access Stratum, NAS, messages are shown in FIG. 2.The numbers below refer to the corresponding numbers shown in thesequence diagram of FIG. 2.

1. An UE/MS initiates any of the procedure listed in table 1. The PCOfield of the request message indicates that the UE/MS supports theenhanced TFT format.

2. If the BBF understands the provided extended TFT indicator in thePCO, it applies the following logic: If the UE/MS indicates support forthe extended TFT, and the network also supports this format, then theextended format will be used. If either the UE/MS or the network haven'timplemented the extended TFT format, or if the UE/MS did not provide theindicator in the PCO field, then the “legacy” TFT format shall be used,i.e. a TFT format of a lower IP-version, preferably IPv4.

3. A response to the PDN connectivity request in step 1 is issued thataccepts the PDN connection. If the UE/MS has indicated its support forthe extended TFT format, and in addition this format is supported by thenetwork, then an indication that the extended TFT format is supportedand will be used for this PDN connection is provided in the PCO field inthe response message. Otherwise, no indication or a negative indicationis provided in the PCO field.

FIG. 3 shows a high level flow diagram 300 of the UE/MS functionalitywhen the invention is used. The numbers below refer to the referencenumbers indicated for the blocks in FIG. 3.

305. The UE/MS initiates any of the procedure listed in Fel! Hittar intereferenskälla. The PCO field of the request message indicates that theUE/MS supports the enhanced TFT format.

310. A positive response to the request issued in step 1 is received.

315. If the Gateway node indicates support for the extended TFT formatin the PCO field in the response message, then the UE/MS will decidethat the extended TFT format should be used. If the network did notindicate support for the extended TFT format, or in case the indicatorwas missing in the PCO field for some other reason, then the UE/MS willdecide that the “legacy” TFT format must be used, i.e. a TFT format of alower IP version, here suitably IPv4.

320. If the GW indicated support for extended TFT, then the extended TFTformat is available for use in all applicable procedures for thelifetime of this PDN connection. The UE/MS may issue resource requestsusing the extended format.

325. If the GW did not indicate support for the extended TFT, then thelegacy TFT format will be used in all applicable procedure for thelifetime of this PDN connection. The UE/MS should not issue resourcerequests using the extended TFT format.

FIG. 4 shows a high level flow diagram 400 of the invention at the“gateway node” end of the system. The numbers below refer to thecorresponding numbers shown in the sequence diagram of FIG. 4.

405. A PDN Connectivity request is received. (Applicable for any of theprocedures listed in section table 1.)

410. Given that the BBF understands the provided extended TFT indicatorin the PCO, the BBF applies the following logic: If the UE/MS indicatessupport for the extended TFT, and in addition the network also supportsthis format, then the extended format will be used. If either the UE/MSor the network haven't implemented the extended TFT format, or if theUE/MS did not provide the indicator in the PCO field for some otherreason, then the legacy TFT format will be used.

NOTE: Network support for the extended TFT format must be configured ineach BBF if BBF relocation is a possibility, i.e. even if the BBFsupports the extended format it must be guaranteed that for all“potential” BBFs that a PDN connection might be relocated to must alsosupport the new format. If this cannot be guaranteed, then the BBFshould suitably be configured to apply the legacy TFT format, i.e. inthis vase IPv4.

NOTE: If the BBF does not understand the indicator itself in the PCOfield (e.g. if it is an “old” BBF) then the BBF will still act accordingto steps 415 and 425 as this is the legacy behavior according to the3GPP standard.

415. The BBF decides that the legacy TFT format applies. A standardresponse to the PDN connectivity request in step 405 is issued thataccepts the PDN connection.

420. The BBF decides that the extended TFT format applies. A response tothe PDN connectivity request in step 405 is issued that accepts the PDNconnection. An indication that the extended TFT format is supported andwill be used is provided in the PCO field in the response message to theUE/MS.

425. Legacy TFT format should be used in all applicable procedures forthe lifetime of this PDN connection. The BBF should not issue networkinitiated resource requests (if applicable) using the extended TFTformat.

430. The extended TFT format should be used in all applicable proceduresfor the lifetime of this PDN connection. The BBF may issue networkinitiated resource requests (if applicable) using the extended TFTformat.

In some embodiments, the extended definition TFT definition which hasbeen mentioned includes so called Link Local Addresses, LLAs.

The invention is not limited to the examples of embodiments describedabove and shown in the drawings, but may be freely varied within thescope of the appended claims.

The invention claimed is:
 1. A user terminal for a wirelesscommunications system, the user terminal being arranged to: establish acommunications session with a gateway node in the wirelesscommunications system according to the Internet Protocol over at leastone bearer; provide a Protocol Configuration Option (PCO) field to thegateway node during the establishment of the session, the PCO fieldincluding an indicator that indicates that the user terminal is arrangedto handle traffic to and from the gateway node using the IPv6 version ofa Traffic Flow Template (TFT); receive a response from the gateway nodeto said indicator in the PCO field; identify an indicator in saidresponse, said indicator indicating that the gateway node can transmitand receive messages according to said version of the TFT; and formatmessages the user terminal sends to the gateway node according to theIPv4 version of the TFT in response to determining said indicator in thePCO field is missing.
 2. The user terminal of claim 1, being a UserEquipment (UE) of an Evolved Packet system.
 3. The user terminal ofclaim 1, being a Mobile Station (MS) of a General Packet Radio Service(GPRS) system.
 4. The user terminal of claim 1, being further arrangedto: receive a response from the gateway node in response to the userterminal providing the PCO field, said response from the gateway nodeincluding a PCO field; and format messages the user terminal sends tothe gateway node according to the IPv4 version of the TFT in response todetermining that the response received from the gateway node is missingan indicator in the PCO field that indicates that the gateway node cantransmit and receive messages according to the IPv6 version of the TFT.5. A gateway node for a wireless communications system, the gateway nodebeing arranged to: establish a communications session according to theInternet Protocol with a user terminal in the wireless communicationssystem over at least one bearer, the gateway node being equipped with afunction for choosng the proper bearer for messages to the userterminal; receive an indicator in a Protocol Configuration Option (PCO)field from the user terminal during the establishment of the session; inresponse to determining that said indicator in the PCO field isreceived, use the IPv6 version of a Traffic Flow Template (TFT) whenchoosing the proper bearer; and format messages the gateway node sendsto the user terminal according to the IPv4 version of the TFT inresponse to determining said indicator in the PCO field is missing. 6.The gateway node of claim 5, wherein said function for choosing theproper bearer is the Bearer Binding Function.
 7. The gateway node ofclaim 6, being a Packet Data Network Gateway for an Evolved PacketSystem.
 8. The gateway node of claim 6, being a Gateway GPRS SupportNode for a General Packet Radio System.
 9. The gateway node according toclaim 5, being further arranged to: transmit a response to the userterminal in response to the user terminal providing the PCO field,wherein in response to determining that the gateway node can transmitand receive messages according to the IPv6 version of the TFT, saidresponse transmitted to the terminal including a PCO field that includesan indicator indicating that the gateway node can transmit and receivemessages according to the IPv6 version of the TFT.